Lignocellulosic feedstock can be used to make one or more biochemicals (e.g., ethanol) in a biorefinery. For example, lignocellulosic feedstock can include one or more polysaccharide molecules (e.g., hemicellulose and/or cellulose) that can be broken down using a variety of techniques to create monosaccharides. The monosaccharides can be used by a microorganism (e.g., yeast) to create one or more biochemicals via a biochemical conversion process such as fermentation. The biochemical(s) can be concentrated by a variety of techniques such as distillation.
Handling and/or processing lignocellulosic feedstock in a biorefinery to form monosaccharides and/or a biochemical such as ethanol can involve one or more challenges due to, e.g., the size and/or bulk density of the lignocellulosic feedstock. For example, lignocellulosic feedstock such as agricultural residue (e.g., corn stover) can be ground to facilitate processing it to produce one or more biochemicals. In some instances, corn stover can be harvested, baled, and transported to a facility that produces biochemicals. The bales of corn stover can be unbaled at the biorefinery and ground to an average size of 10 inches or less, or even 4 inches or less. The ground corn stover can be transported within the biorefinery via a conveying system. If the ground corn stover is being transferred through an opening, the ground corn stover can bridge across the opening and pile up to an undue degree. In some embodiments, the ground corn stover can pile up in a manner so as to prevent flow of the ground corn stover through the opening which can damage equipment in the conveying system. Because of the bulk density of the ground stover, such conveying systems can be relatively large and occupy a substantial amount of space within a biorefinery.
Another example of a challenge related to processing lignocellulosic feedstock involves processing lignocellulosic feedstock in an apparatus that separates liquids from solids. For example, lignocellulosic feedstock such as corn stover can be ground and mixed with a liquid aqueous composition such as water to form a slurry and treat the ground corn stover. The ground corn stover in the slurry can be treated to break down polysaccharides (e.g., hemicellulose and/or cellulose) into oligosaccharides and/or monosaccharides (e.g., pentose and/or hexose). After treating the ground corn stover in the slurry, at least a portion of the remaining solids from the ground corn stover can be separated from at least a portion of the liquid in the slurry. In some instances, a screen can be used to separate the remaining solids from the liquid. The remaining ground corn stover solids can be relatively straight fibrous material that can plug the screen to an undue degree. In some embodiments, the remaining corn stover solids can build up to a degree that substantially prevents liquid from passing through the screen.